A new family of bis-ureidic receptors for pyrophosphate optical sensing.

A new family of bis-ureidic receptors (L(1)-L(6)) has been synthesised. The binding properties of L(1)-L(6) towards different anions (acetate, benzoate, glutarate, malonate, dihydrogen phosphate, hydrogen pyrophosphate, triphosphate, AMP and ADP) have been studied by means of (1)H-NMR, UV-Vis and fluorescence spectroscopies and a remarkable affinity for HPpi(3-) has been observed in the case L(3) (in DMSO-d6 and DMSO-d6-5% H2O) which also acts as a fluorimetric chemosensor, even to the naked eye, for this anion. Theoretical calculations helped us explain the binding properties observed.